Grouse drumming and turkey drumming are totally different. Turkeys don' t produce the drumming sound by rapid flapping of their wings (as grouse do), it is produced somewhere internally. The " spit" sound before the " drum" is produced by a quick inhalation/exhalition of air. The origin of the actual drumming is sort of a biological mystery.

Seems to me everytime they drop strut and then fan out again, they spit and drum. I' ve also heard gobblers drum over and over without breaking strut.

Tyler